<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap@4.6.2/dist/css/bootstrap.min.css" integrity="sha384-xOolHFLEh07PJGoPkLv1IbcEPTNtaed2xpHsD9ESMhqIYd0nLMwNLD69Npy4HI+N" crossorigin="anonymous">
    <script src="https://cdn.jsdelivr.net/npm/jquery@3.5.1/dist/jquery.slim.min.js" integrity="sha384-DfXdz2htPH0lsSSs5nCTpuj/zy4C+OGpamoFVy38MVBnE+IbbVYUew+OrCXaRkfj" crossorigin="anonymous"></script>
    <script src="https://cdn.jsdelivr.net/npm/bootstrap@4.6.2/dist/js/bootstrap.bundle.min.js" integrity="sha384-7ymO4nGrkm372HoSbq1OY2DP4pEZnMiA+E0F3zPr+JQQtQ82gQ1HPY3QIVtztVua" crossorigin="anonymous"></script>
</head>
<body>
    <div style="width: 500px; height: 400px;">
        <nav class="navbar navbar-expand-lg navbar-dark bg-primary">
        <a class="navbar-brand" href="#">首页</a>
        <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarNavAltMarkup" aria-controls="navbarNavAltMarkup" aria-expanded="false" aria-label="Toggle navigation">
          <span class="navbar-toggler-icon"></span>
        </button>
        <div class="collapse navbar-collapse" id="navbarNavAltMarkup">
          <div class="navbar-nav">
            <a class="nav-link active" href="#">我的 <span class="sr-only">(current)</span></a>
            <a class="nav-link" href="#">设置</a>
            <li class="nav-item dropdown">
                <a class="nav-link dropdown-toggle" href="#" role="button" data-toggle="dropdown" aria-expanded="false">
                  更多
                </a>
                <div class="dropdown-menu">
                  <a class="dropdown-item" href="#">Action</a>
                  <a class="dropdown-item" href="#">Another action</a>
                  <a class="dropdown-item" href="#">Something else here</a>
                </div>
              </li>
            <a class="nav-link disabled">退出</a>
          </div>
        </div>
      </nav>
      <form>
        <div class="form-group">
          <label for="exampleFormControlInput1">账号</label>
          <input type="email" class="form-control" id="exampleInputEmail1" aria-describedby="emailHelp">
        </div>
        <div class="form-group">
            <label for="exampleFormControlInput1">密码</label>
            <input type="email" class="form-control" id="exampleInputEmail1" aria-describedby="emailHelp">
          </div>
        <div class="form-group" style="width: 200px;">
          <label for="exampleFormControlSelect1">选择登入</label>
          <select class="form-control" id="exampleFormControlSelect1">
            <option>移动登入</option>
            <option>电信登入</option>
            <option>联通登入</option>
          </select>
        </div>
        <button type="submit" class="btn btn-primary">登入</button>
    </form>
    </div>
    
</body>
</html>